Detection of composite forged image

With the development of digital technology, original analog photograph has been increasingly replaced by digital image, and the forgery of digital image has become more and more easy and diversiform. For the most common blur operations of composite forged image, this paper presents a localization approach of forged region based on detection of image edge. First of all, we process the image, which is to be detected, with a smoothing filter, and then use the LOG (Laplace-Gaussian Operator) edge detector for edge detection, finally, we make judgment on missed edge: if the forged region is connected and its size is not less than 0.85% of the whole image´s size, we can judge this forgery is significative. Experimental results demonstrate that the proposed approach can accurately detect the blur operation traces of composite forged images, and can precisely locate the forged region.